Add-on not showing up in Blender 2.82
(I don't have the reputation to comment this: Powroupi's latest version of Blender MMD Tools works through version 2.90 (my version). Download it here.)
As mentioned by Kisracora, the plugin needs to be unzipped before the mmd_tools folder can be inserted into the addons folder. (If you're on Windows, you can simply enter the zip folder without unzipping and click-drag the mmd_tools folder in.) If doing that and enabling the plugin in Blender DOESN'T get it to show up, you may want to try rightclick &gt; Properties &gt; Unblock the zip (checkbox near the bottom of the Properties window).